The present invention pertains to hearing aids, and in particular, to a hearing aid including an internal rechargeable battery mounted within the hearing aid.
Hearing aids typically include a battery for energizing the electrical components within the hearing aid. Hearing aids are known which include a battery removably carried with the hearing aid casing. For example, U.S. Pat. No. Re. 26,174 entitled HEARING AID and which issued to Leale on Mar. 21, 1967, discloses a battery holder which may be inserted and removed from the hearing aid to replace a battery carried therein. The holder provides easy access to the hearing aid battery as the user need not disassemble the hearing aid. However, new batteries must be purchased each time an old battery no longer has a sufficient charge for the hearing aid components, which is relatively costly. Furthermore, the appearance of hearing aids is very important to wearers, as an unattractive casing accents the fact that a hearing aid is inserted in the user's ear. A significant disadvantage of the hearing aids with doors is the doors are unattractive and discourage use of the hearing aid.
In-the-canal and over-the-ear hearing aids include replaceable batteries. These hearing aids consequently require that the batteries therein be replaced on a regular basis. Over-the-ear hearing aids include amplification circuits for users with severe hearing loss and use especially costly batteries. Regardless of whether the hearing aids are in-the-ear or over-the-ear, and regardless of the amplification provided by the hearing aid, the batteries must be replaced often. Because the batteries are costly to replace, these hearing aids are costly to maintain.
In-the-ear hearing aids are known which include externally accessible contacts coupled to an internal rechargeable battery. For example, U.S. Pat. No. 3,354,271 entitled SEALED HEARING AID and which issued to McDermaid on Mar. 21, 1967, discloses a hearing aid including contacts on the surface of the hearing aid through which charging current is supplied to a battery from a charger. The hearing aid does not include a door on the surface of the hearing aid casing. The charger is relatively heavy and large. It must be carried with the hearing aid in order to charge the internal battery. Such chargers must be plugged into the openings on the hearing aid. The small contacts of the plug can be difficult to manipulate into connection with the contacts on the hearing aid.
Solar powered hearing aids are known which allow the hearing aid battery to be charged from solar cells. One such hearing aid is disclosed in U.S. Pat. No. 2,901,551 entitled EYEGLASS HEARING AID and which issued to Passow on Aug. 25, 1959. As disclosed, an eyeglass frame has solar cells for supplying charging current to an internal rechargeable battery. The solar cell construction of the Passow patent cannot be used on an in-the-ear hearing aid due to the large array of the solar cells. Furthermore, the dark light responsive surface of the solar cells is visible through a transparent cover.
Another solar cell hearing aid includes a solar cell which is coupled to an internal rechargeable battery. The solar cell is mounted on the outside surface of the hearing aid casing behind a flesh colored door. To charge the solar cell, the door must be open. The door often falls off and is difficult to manipulate. Additionally, because the door is on the outside surface of the hearing aid, it is visible when the hearing aid is located within the user's ear. The door is unattractive and diminishes the appearance of the hearing aid.